I was a primarily PVC installer, but I did use Poly in some situtations. The largest poly I ever used was 2" for a suction line for a pump (Fed it out 15' into a lake and staked it so it was about 6' under water. Anyways, aside from getting prohibitivly expensive, Poly that size is a real bear to handle compared to PVC. Does anyone use big poly? 2" and above?